Which of the following equations correctly expresses the self-ionization of water?

• A. 2 H_2O(l) ightarrow H_3O^+(aq) + OH^-(aq)
• B. H_2O(l) ightarrow H^+(aq) + OH^-(aq)
• C. 2 H_2O(l) ightarrow H_2(g) + O_2(g)
• D. H_2O(l) + OH^-(aq) ightarrow H_3O^+(aq)

Answer: (A)

Verified step by step guidance

1. Recall that the self-ionization of water involves water molecules reacting with each other to produce hydronium and hydroxide ions.
2. Write the general form of the self-ionization reaction: two water molecules interact, where one donates a proton (H\^+) to the other.
3. Express this reaction as: \$2\ H\_2O(l) \rightarrow H\_3O\^+(aq) + OH\^-(aq)$, showing the formation of hydronium and hydroxide ions.
4. Check the other options: the reaction producing \(H\^+(aq)\) and \(OH\^-(aq)\) directly from one water molecule is a simplified representation but less accurate than the hydronium ion form.
5. Confirm that the reactions producing gases (\(H\_2\) and \(O\_2\)) or involving hydroxide reacting with water to form hydronium are not representative of the self-ionization process.